This invention relates to a soil penetrating device and more particularly to a means operably associated with the penetrating device for pulling flexible duct through the area penetrated by the device.
In the utility industry it has been customary for many years to use air-powered or hydraulic piercing rams to make horizontal bores in soil under roadways and railways. These horizontal holes are generally fitted with pipe, ducts or conduits for gas or electric lines. The horizontal boring under a roadway or railway eliminates the necessity of trenching, backfilling, and repaving the roadway or railway under which the pipe is to be placed. Further, this procedure eliminates the problems encountered by stopping traffic on the roadway or railway. The general procedure for placing the pipe or conduit in the hole is to push the pipe through the hole after it is formed. This procedure is not always possible since often, after the hole is bored, the walls around the hole collapse. Several devices for simultaneously pushing pipe or duct through holes as they are formed have been used. These devices eliminate the problem of the walls surrounding the hole collapsing prior to the insertion of the pipe but are designed to be used with rigid pipe. A device of this type generally has the soil penetrating member mounted on one end of a rigid section of pipe while the other end of pipe is mounted to a drive mechanism. The force generated by the drive mechanism is transferred through the rigid pipe section to the soil penetrating member. The forces transferred through the pipe are compressive in nature thereby requiring a rigid pipe to adequately transfer the force. The advent of flexible pipe essentially eliminated the use of this device since the pipe can no longer adequately transmit the force necessary to drive the soil penetrating member. In fact the application of this type of force can severely compress and damage certain types of flexible piping. This invention is directed to an apparatus designed to simultaneously pull flexible duct through a hole in soil as the hole is being formed.